Sleep apnea

Definition
Sleep apnea, also called sleep apnea syndrome, is a condition in which breathing is recurrently disrupted during periods of sleep. The episodes often last 10 to 30 seconds. Sometimes the episodes last two to three minutes. Although sleep apnea occasionally affects infants and children, we'll focus on sleep apnea in adults.

Types of sleep apnea
There are two major types of sleep apnea.
With central sleep apnea, breathing stops for the entire episode. Considered uncommon, this type of sleep apnea is typically seen in people over age 60. Cheyne-Stokes respiration is a type of central sleep apnea marked by accentuated breathing and episodes of stopped breathing.

Breathing continues with obstructive sleep apnea, but an airway blockage temporarily stops the airflow. The most common type of sleep apnea, obstructive sleep apnea affects about 4 percent of middle-aged men and 2 percent of middle-aged women.
Apneic episodes may happen up to 300 or more times per night. A strong gasp for air and a loud snort usually follow the first breath after each episode. Most people with sleep apnea are extremely tired when they're awake. They may even fall asleep suddenly during the day, which can have potentially life-threatening consequences.


Causes/associated factors
Until women reach menopause, sleep apnea affects men more often. In fact, the most common profile of a person with sleep apnea is an overweight, middle-aged man. Possibly because of hormonal changes, the incidence of sleep apnea for women approaches that of men after menopause.
In general, sleep apnea may be related to certain disorders of the heart, lungs, nervous system (including the brain and spinal cord) or skeletal muscles. Risk factors for sleep apnea include:

a family history of the condition
aging
obesity
high blood pressure or heart disease
alcohol or drug use
hypothyroidism (underactive thyroid, the gland that, in part, helps regulate the body's metabolism)
nasal obstruction, such as a deviated septum or nasal polyps (growths)
cigarette smoking
Central sleep apnea is thought to be related to an abnormality of the brain's normal signal to breathe. It may be seen in people who have primary alveolar hypoventilation (reduced rate and depth of breathing within the air passages in the lungs that causes an increase in carbon dioxide level in the blood) or brain stem lesions (wounds or injuries). Cheyne-Stokes respiration is seen in people who have congestive heart failure.

Obstructive sleep apnea is related to an airway blockage. The condition is also related to aging -- as you get older, neck muscles tend to lose their tone, become smaller and develop fatty deposits. These heavy, sagging muscles may allow the airway to collapse while you're trying to breathe. Obesity can lead to obstructive sleep apnea by increasing fat deposits in the airway or compressing the airway, both of which increase upper airway resistance. You're also more likely to develop obstructive sleep apnea if you have:

a small airway
large tonsils
a large tongue
a small jaw
acromegaly (a chronic disease that may cause jaw enlargement)
hypothyroidism (underactive thyroid, the gland that helps regulate metabolism)
Marfan's syndrome (an inherited disorder that causes anatomical structures made of connective tissue to weaken)
Smoking cigarettes, drinking alcohol or using sedatives (especially before bedtime) can encourage sleep apnea or make it worse. Nasal stuffiness from allergies, colds or any other cause can also be a factor.


Signs/symptoms
Symptoms of sleep apnea may include:
excessive daytime sleepiness and fatigue
morning sluggishness and headaches
difficulty concentrating
weight gain
decreased sex drive or, for men, erectile dysfunction (impotence)
irritability
depression
Household members may also notice:

loud cyclical snoring
"stopped" breathing
thrashing around during sleep
restlessness
lack of judgment
personality changes

Diagnosis
A combination of tests and evaluations can help your doctor diagnose sleep apnea.
Health history
First, the doctor considers possible causes of coexisting conditions. A history of snoring or breathing abnormalities described by a bed partner is key. Five to 10 percent of people snore when sleeping. By age 50, 30 to 50 percent of people snore. Other factors the doctor will consider include:

drug use
seizure disorders, including night seizures
narcolepsy (a condition that causes a person to fall asleep uncontrollably)
clinical depression
nighttime asthma
gastroesophageal reflux (backward flow of stomach acid into the esophagus, the tube that connects the throat and stomach)
swallowing problems
stridor (a high-pitched, harsh sound made when breathing, due to obstruction of the upper airway)
night terrors (sudden awakenings from a deep sleep accompanied by normal responses to fear)
restless leg syndrome (uncontrollable leg twitching)
Physical exam
Next, the doctor studies the bones of the face, jaw, palate (roof of the mouth), uvula (soft tissue hanging from the back of the throat) and tonsils while you sit or lie in various positions. The doctor may detect soft tissue folds, large tonsils, a dangling uvula or large tongue.

The physical exam may also reveal poor nasal airflow, a deviated septum (crooked wall between the nostrils that narrows the air passage and makes breathing difficult) or failure of the right ventricle (one of the pumping chambers of the heart). The doctor will listen for a nasal tone to your voice and look for a "bull-neck" appearance. Sometimes, people who have sleep apnea appear very sleepy or even fall asleep during the exam.

Medical tests
Lab studies, such as blood and thyroid tests, may be done to confirm the diagnosis. The doctor may also do a skull X-ray or endoscopy (examination with an endoscope, a thin, flexible tube equipped with a camera lens and light) to see the size of the spaces the inhaled air must pass through. A neck X-ray, computed tomography (CT scan -- a computer-generated, cross-sectional picture of internal body parts) or magnetic resonance imaging (MRI, an imaging technique based on computer analysis of the body's response to a magnetic field) may also help the doctor make a diagnosis.

Sleep study
An overnight sleep study called polysomnography is considered the most reliable diagnostic tool to confirm sleep apnea. This study may be done in a sleep lab or hospital. You'll arrive at the lab or hospital about one hour before your normal bedtime. If you usually have a drink before bed, you'll do the same thing in the sleep lab.

While you sleep, sensors measure your heart rate, brain wave patterns, muscle activity, and leg, arm and eye movements. An elastic band containing special gauges is placed around your chest and abdomen to record muscle movements during breathing. A mask is placed over your nose and mouth to help the doctor track breathing rate and apneic episodes. An oximetry probe on your finger, toe or ear monitors the amount of oxygen in your blood. Your heart rate is also monitored for any abnormalities. In some cases, less sophisticated home devices (also called portable polysomnography) may be used to initially screen someone suspected of having obstructive sleep apnea. However, evidence is not yet clear concerning the use of these home tests.

You may be diagnosed with sleep apnea if:

you had more than 30 episodes of interrupted breathing lasting 10 seconds or longer during the night
you had an irregular heartbeat with fluctuations in heart rate
you woke up often
there were dips in the amount of oxygen in your blood
you continued to try to breathe when airflow from your nose and mouth stopped (which indicates obstructive sleep apnea) or you stopped trying to breathe during apneic episodes (which indicates central sleep apnea)

Treatment
Treatment for sleep apnea depends on the cause, severity of the disorder or the amount of daytime sleepiness you may exhibit. If you have mild sleep apnea, it may be as simple as sleeping on your side or taking a decongestant to clear up nasal stuffiness. Weight reduction may also be recommended.
Cause: Upper airway muscle tone
If you have mild to moderate sleep apnea related to upper airway muscle tone, you may be advised to avoid alcohol and sedatives.

Cause: Lumen size
If the problem is lumen size (the space air passes through), treatment may include weight loss or sleeping on your side. Mouth devices can hold your jaw forward and your tongue back or raise the roof of your mouth.

For more severe cases, an outpatient procedure called uvulopalatopharyngoplasty (UPPP) may be recommended. With this procedure, the doctor creates a larger airway by removing the back part of the soft palate and the tissue at the back of the throat. UPPP improves sleep apnea for about half of surgical patients. The doctor will often study a lateral picture of the skull to help determine if surgery will be successful.

To treat snoring, but not necessarily sleep apnea, the doctor may recommend an outpatient procedure called laser-assisted uvuloplasty (LAUP). A procedure called radiofrequency volumetric tissue reduction of the palate is also currently being used to treat snoring. Results thus far are being evaluated.

Cause: Lack of airway pressure
If the sleep apnea is related to lack of airway pressure, keeping the nasal passages open through continuous positive airway pressure (CPAP) can be helpful. With CPAP, you sleep with a nasal mask strapped to your head and small tubes in your nostrils. The mask is connected to a motor that controls the quantity and pressure of air sent to your nasal passages. At the same time, the positive pressure holds open the nasal passages and the back of the throat. An overnight sleep study may be done to help your doctor determine the appropriate pressure level.

CPAP is the most common medical treatment for sleep apnea. About 75 percent of patients continue CPAP on a long-term basis.

For more severe cases related to lack of airway pressure, it may be helpful to permanently open the nasal passages. A surgical procedure called nasal septoplasty may be recommended if you have a large deformity in the septum (the wall between the nostrils).

More aggressive treatments
For severe cases of obstructive sleep apnea, a tracheotomy (making a hole in the front of the neck to help you breathe) may be necessary. This surgery is normally reserved for people who cannot tolerate CPAP and have severe high blood pressure with a high risk of heart failure due to sleep apnea.

If you've had no relief from more conservative measures and your sleep apnea causes life-threatening irregular heartbeats or severe disability, the doctor may recommend maxillofacial surgery. This procedure, also called maxillary or mandibular advancement, involves fracturing the jaw and moving it forward to create a larger air space.

Follow-up
About three to six months after treatment begins or as recommend by the doctor, you may need a follow-up evaluation in the sleep lab or hospital.


Complications
When sleep apnea leaves you without enough oxygen in your blood at night, you may develop:
heart failure
pulmonary hypertension (high blood pressure in the arteries in the lungs)
cor pulmonale (a type of heart failure)
secondary erythrocytosis (an abnormally high number of red blood cells)
ventricular arrhythmias (irregular contractions in the ventricles, the pumping chambers of the heart)
severe hypoxemia (not enough oxygen in the blood) during sleep
When you stop breathing repeatedly during the night, your body's oxygen supply is reduced. This can be hard on your heart and blood vessels. As a result, people with sleep apnea are two to three times more likely to have high blood pressure and three times more likely to have a stroke. The risk of complications increases with age and weight.

Even when breathing is normal, nighttime high blood pressure related to sleep apnea may persist during the day. Also, the inattentiveness and daytime sleepiness often associated with sleep apnea may contribute to potentially life-threatening accidents. In fact, people who have sleep apnea are two to five times more likely than the average person to have an automobile accident.


Pregnancy-specific information
Sleep apnea is rare during pregnancy.

Senior-specific information
Again, sleep apnea is commonly associated with aging. For older adults, especially men with heart disease, sleep apnea is often one of numerous coexisting health conditions.

Prevention
To prevent sleep apnea, maintain an optimal weight and avoid alcohol and sleeping pills. Try not to sleep on your back. Seek medical help to minimize or improve your symptoms and treat any underlying causes. To prevent accidents, avoid activities that require mental alertness (such as driving or operating equipment) when you're sleepy -- even if it's the middle of the day.